The present invention relates to manifolds for diaphragm protected components, through which a fluid flows, and in particular to such a manifold for a pressure transducer for fluids which may readily be flushed of fluid of one type in preparation for a flow therethrough of fluid of another type.
Pressure transducers are often used in connection with spray coating systems, and are placed in line with a paint supply line to a spray paint apparatus to sense the pressure of paint in the line and to generate an indication of system failure in the absence of pressure. Such transducers conventionally comprise a circular recess in a housing and a diaphragm of flexible material sealed with the housing over and around the recess. Inlet and outlet passages communicate with the recess adjacent its circumference at positions approximately 180.degree. apart to form a manifold with the housing and diaphragm and means, such as a microswitch, senses outward deflection of the diaphragm in response to pressure of paint in the manifold.
When articles are required to be coated a wide variety of colors, it is generally not practical to establish separate spray stations or production lines for each color, or even spray a long sequence of articles one color, then another long sequence of articles a second color, etc. Instead, it is desirable to be able to make color changes rapidly and simply at a single spray station, and for the purpose color change systems are useful. With such systems a plurality of supply containers of paint, each of a different color, are connected with a manifold through valve controlled ports. An outlet from the manifold is connected, for example through a metering pump, with the paint supply line, and to spray paint of a particular color the port valve associated therewith is opened to provide the paint through the manifold to the supply line. After completion of spraying articles one color the manifold, metering pump, supply line, pressure transducer and spraying apparatus are flushed with solvent and compressed air to clean the system in preparation for spraying articles another color.
For rapid color changes on high volume production lines, it is necessary that system components be capable of being rapidly flushed by flushing media during color change operations. Unfortunately, conventional pressure transducers of the type described are not readily flushable of coating material, since in such transducers "dead end" spaces exist in the manifold to the sides of the inlet and outlet and flushing media tends to follow a straight line path of least resistance between the inlet and outlet. Consequently, unless the flushing intervals are excessively long, which usually cannot be accommodated in high volume production lines, the entirety of the surfaces of the manifold are not cleaned and subsequently supplied paint is contaminated.